Medical punches are cutting tools with a rigid cutting edge and a cutting edge that can slide with respect to the rigid cutting edge, such that the two cutting edges are not capable of pivoting with respect to one another around a pivot point, as with a scissors or the like, but rather as a rule can be displaced horizontally with respect to one another.
With medical punches common in the art, the instrument shaft is configured as a hollow shaft in which a push/pull device, which is connected with the displaceable cutting edge and can be driven by the handle, is displaceably mounted. These punches have thoroughly proven themselves in the art, but in practice, in particular with stamps whose cutting edges are configured at an incline of 45 degrees with respect to the instrument's longitudinal axis, the cutting edges can go out of alignment when the cutting edges are slid into the punching or closing position. This slipping outward of the cutting edges from their axially parallel alignment to one another prevents a precise actuation of the medical punch.
To align the cutting edges of a medical punch axially parallel to one another, it is known, for instance from patent DE 28 08 911 C2, to secure the displaceable hollow outer tube with the rigid inner rod by means of a groove-and-tongue joint with respect to one another. The disadvantage of this known construction is, on the one hand, the high manufacturing cost of configuring the compatible anti-tilt mechanism and, on the other hand, the inflexibility concerning replacements of the cutting parts.
Consequently it is the object of the invention to design a medical punch of the aforementioned type in such a way that it is of simple construction and ensures a constantly exact guidance of the cutting parts with respect to one another.